rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=8444/1/0x4000000000000004 softirq=30073/30074 fqs=206 rcu: (t=10500 jiffies g=25149 q=85 ncpus=2) rcu: rcu_preempt kthread starved for 10082 jiffies! g25149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27400 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.15.0-rc5-syzkaller-00032-g0d8d44db295c #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 eb 11 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 0348f1887c87b600 RBX: ffffffff81974f28 RCX: 0348f1887c87b600 RDX: 0000000000000001 RSI: ffffffff8d74aa4f RDI: ffffffff8bc1d1e0 RBP: ffffc90000197f20 R08: ffff8880b8932b5b R09: 1ffff1101712656b R10: dffffc0000000000 R11: ffffed101712656c R12: ffffffff8f7ed970 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110037d6b40 FS: 0000000000000000(0000) GS:ffff8881261cb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5ce32a6910 CR3: 000000003261e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc5-syzkaller-00032-g0d8d44db295c #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 RIP: 0010:qdisc_peek_head+0x29/0x40 include/net/sch_generic.h:1117 Code: 90 f3 0f 1e fa 53 48 89 fb e8 c3 9e 55 f8 48 81 c3 d8 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 2d 93 b7 f8 48 8b 03 5b c3 cc cc cc cc cc 0f 1f RSP: 0018:ffffc90000007ad0 EFLAGS: 00000246 RAX: 1ffff1100f68991b RBX: ffff88807b44c8d8 RCX: dffffc0000000000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff88807b44c800 RBP: ffff888027039000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff896a3180 R12: dffffc0000000000 R13: ffff8880611ec000 R14: ffff88807b44c800 R15: ffffffff8f7f5f38 FS: 0000000000000000(0000) GS:ffff8881260cb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f97c5771da0 CR3: 0000000033084000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: taprio_dequeue_from_txq+0x171/0x900 net/sched/sch_taprio.c:720 taprio_dequeue_tc_priority+0x1ac/0x750 net/sched/sch_taprio.c:787 taprio_dequeue+0x186/0x550 net/sched/sch_taprio.c:-1 dequeue_skb net/sched/sch_generic.c:293 [inline] qdisc_restart net/sched/sch_generic.c:398 [inline] __qdisc_run+0x239/0x15f0 net/sched/sch_generic.c:416 qdisc_run+0xc2/0x230 include/net/pkt_sched.h:127 net_tx_action+0x7c9/0x980 net/core/dev.c:5534 handle_softirqs+0x283/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:sched_core_balance+0x156/0xf00 kernel/sched/core.c:6413 Code: 4c 6a 8b e8 1c 43 0b 00 4c 89 74 24 68 4c 89 7c 24 48 e9 3b 0d 00 00 4c 89 f7 e8 45 a4 c5 09 e8 f0 47 34 00 fb 48 8b 5c 24 70 <83> fb 08 0f 83 06 0d 00 00 4c 8d 34 dd 10 dc 96 8d 4c 89 f0 48 c1 RSP: 0018:ffffffff8dc07980 EFLAGS: 00000282 RAX: 27159aae7f9f5a00 RBX: 0000000000000000 RCX: 27159aae7f9f5a00 RDX: 0000000000000000 RSI: ffffffff8d74aa4f RDI: ffffffff8bc1d1e0 RBP: ffffffff8dc07ae8 R08: ffffffff8f7ed977 R09: 1ffffffff1efdb2e R10: dffffc0000000000 R11: fffffbfff1efdb2f R12: ffff8880b8839b40 R13: dffffc0000000000 R14: ffff8880b8839b40 R15: 0000000000000000 do_balance_callbacks kernel/sched/core.c:5028 [inline] __balance_callbacks kernel/sched/core.c:5082 [inline] finish_lock_switch kernel/sched/core.c:5129 [inline] finish_task_switch+0x3a4/0x950 kernel/sched/core.c:5248 context_switch kernel/sched/core.c:5385 [inline] __schedule+0x16ea/0x4cd0 kernel/sched/core.c:6767 schedule_idle+0x52/0x90 kernel/sched/core.c:6886 do_idle+0x4ad/0x510 kernel/sched/idle.c:353 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423 rest_init+0x2de/0x300 init/main.c:743 start_kernel+0x470/0x4f0 init/main.c:1099 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494 common_startup_64+0x13e/0x147